Abstract

Collective excitations have been observed in liquid aluminum oxide at high temperatures by combining a containerless sample environment with inelastic x-ray scattering. The excitation spectra show a well-defined triplet peak structure at lower wave vectorsQ (1 to 6 nanometers−1) and a single quasi-elastic peak at higher Q. The high-Qspectra are well described by kinetic theory. The low-Qspectra require a frequency-dependent viscosity and provide previously unknown experimental constraints on the behavior of liquids at the interface between atomistic and continuum theory.

↵* To whom correspondence should be addressed. E-mail: mls{at}cnrs-orleans.fr